On Windows 2012 you need to go to Server manager, then Add Roles and Features. Click next a couple of times till you get to the Server Roles options. From there, expand Application Server and select "Web Server (IIS) Support". Next you need to select Http Activiation and maybe TCP Activation (I did both), this is what enables support for WCF on 2012.
It should select all necessary dependencies for you, but it might be that you also need to go to the "Web Server (IIS)" section, then "Application Development" and select the ASP.NET option that you need (I had already installed these options first, so I don't know if it's necessary to do this or not if only doing the Support option). This will create the .svc handler for you.